You can either continue as usual with an authorized_keys file in
home directories, or look at the LPK patch available for OpenSSH that
allows storing public keys in LDAP.
Having the users in LDAP has absolutely no effect on how key-based
logins work with SSH, but it does open up some other options.
So the easiest route to take might be to dis-allow ssh logins for
everyone except my few authorized users via the /etc/security/access
file? And then to allow exceptions on a case by case basis using this
file as well?